In some special situations there is need for efficient, reliable, high intensity, broad area, essentially monochromatic, light sources. For example, in the optical pumping of a high power, solid-state laser, such as an yttrium aluminum garnet (YA1G) laser, there is a need for a source of substantially monochromatic light of a specific wavelength, and of uniform high intensity over a cross section suitable for irradiating the YA1G crystal. The spatial coherence is not a requirement of such a source. Average power levels of many kilowatts are sometimes required. While at some specific wavelengths, there are available lasers of high average power, such as carbon dioxide lasers; at other specific wavelengths needed for pumping, lasers of high power may be unavailable.